Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Scope and limitations of a novel synthesis of 3-arylazonicotinates.

ABSTRACT: The reaction of 3-oxo-3-phenyl-2-phenylhydrazonal with functionally substituted and heteroaromatic substituted acetonitrile to yield arylazonicotinic acid derivatives and 5-arylsubstituted pyridines was established. In some cases the produced nicotinates could not be isolated as they underwent thermally induced 6?-electrocyclization yielding polynuclear pyridine derivatives.

SUBMITTER: Zaky OS

PROVIDER: S-EPMC6268266 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Scope and limitations of a novel synthesis of 3-arylazonicotinates.

Zaky Omniya Sayed OS Moustafa Moustafa Sherief MS Selim Maghraby Ali MA El-Maghraby Awatef Mohamed AM Elnagdi Mohamed Hilmy MH

Molecules (Basel, Switzerland) 20120518 5

The reaction of 3-oxo-3-phenyl-2-phenylhydrazonal with functionally substituted and heteroaromatic substituted acetonitrile to yield arylazonicotinic acid derivatives and 5-arylsubstituted pyridines was established. In some cases the produced nicotinates could not be isolated as they underwent thermally induced 6π-electrocyclization yielding polynuclear pyridine derivatives. ...[more]

PMID: 22609783

Similar Datasets

Catalytic Asymmetric Synthesis of Ketene Heterodimer ?-Lactones: Scope and Limitations.

Project description:In this article we describe extensive studies of the catalytic asymmetric heterodimerization of ketenes to give ketene heterodimer ?-lactones. The optimal catalytic system was determined to be a cinchona alkaloid derivative (TMS-quinine or Me-quinidine). The desired ketene heterodimer ?-lactones were obtained in good to excellent yields (up to 90%), with excellent levels of enantioselectivity (?90% ee for 33 Z and E isomer examples), good to excellent (Z)-olefin isomer selectivity (?90:10 for 20 examples), and excellent regioselectivity (only one regioisomer formed). Full details of catalyst development studies, catalyst loading investigations, substrate scope exploration, protocol innovations (including double in situ ketene generation for 7 examples), and an application to a cinnabaramide A intermediate are described. The addition of lithium perchlorate (1-2 equiv) as an additive to the alkaloid catalyst system was found to favor formation of the E isomer of the ketene heterodimer. Ten examples were formed with moderate to excellent (E)-olefin isomer selectivity (74:25 to 97:3) and with excellent enantioselectivity (84-98% ee).

| S-EPMC5012991 | biostudies-literature

Enzymatic synthesis of nucleobase-modified UDP-sugars: scope and limitations.

Project description:Glucose-1-phosphate uridylyltransferase in conjunction with UDP-glucose pyrophosphorylase was found to catalyse the conversion of a range of 5-substituted UTP derivatives into the corresponding UDP-galactose derivatives in poor yield. Notably the 5-iodo derivative was not converted to UDP-sugar. In contrast, UDP-glucose pyrophosphorylase in conjunction with inorganic pyrophosphatase was particularly effective at converting 5-substituted UTP derivatives, including the iodo compound, into a range of gluco-configured 5-substituted UDP-sugar derivatives in good yields. Attempts to effect 4"-epimerization of these 5-substituted UDP-glucose with UDP-glucose 4"-epimerase from yeast were unsuccessful, while use of the corresponding enzyme from Erwinia amylovora resulted in efficient epimerization of only 5-iodo-UDP-Glc, but not the corresponding 5-aryl derivatives, to give 5-iodo-UDP-Gal. Given the established potential for Pd-mediated cross-coupling of 5-iodo-UDP-sugars, this provides convenient access to the galacto-configured 5-substituted-UDP-sugars from gluco-configured substrates and 5-iodo-UTP.

| S-EPMC4340641 | biostudies-literature

Scope and Limitations of Xanthate-Mediated Synthesis of Functional γ-Thiolactones.

Project description:A modular platform based on free-radical xanthate addition to alkenes enables access to a large series of functional γ-thiolactones. This methodology includes two different pathways based on xanthate chemistry involving radical addition and Chugaev elimination steps. The first method uses the addition of an ester-functionalized xanthate to various commercially functional alkenes, whereas the second one is based on the addition of functional xanthates to an ester-functionalized alkene. In both cases, a series of xanthate/alkene monoadducts was obtained, and their thermolysis and subsequent cyclization led to a library of functional γ-thiolactones in moderate to good yield. For a few cases where it may not be possible to directly incorporate some targeted functional groups via the proposed process involving free radicals and high temperature, a bromo-functionalized thiolactone was used as a starting material for chemical transformations.

| S-EPMC6644131 | biostudies-literature

Amine-directed hydroboration: scope and limitations.

Project description:Iodine activation induces intramolecular hydroboration of homoallylic and bis-homoallylic amine boranes with good to excellent control of regiochemistry compared to control experiments using excess THF*BH 3. Deuterium labeling and other evidence confirm that the iodine-induced hydroboration reaction of homoallylic amine boranes occurs via an intramolecular mechanism equivalent to the classical 4-center process and without competing retro-hydroboration. Longer carbon chain tethers result in lower regioselectivity, whereas the shorter tether in allylic amines results in a switch to dominant intermolecular hydroboration. Regioselectivity in THF*BH 3 control experiments is higher for the allylic amine boranes compared to the iodine activation experiments, whereas the reverse is true for homoallylic amine borane activation.

| S-EPMC2646876 | biostudies-other

Palladium-catalyzed synthesis of tetrahydrofurans from gamma-hydroxy terminal alkenes: scope, limitations, and stereoselectivity.

Project description:A new, stereoselective synthesis of substituted tetrahydrofurans via Pd-catalyzed reactions of aryl and vinyl bromides with gamma-hydroxy terminal alkenes is described. This transformation affords trans-2,5- and trans-2,3-disubstituted tetrahydrofurans with up to >20:1 dr. This methodology also provides access to bicyclic and spirocyclic tetrahydrofuran derivatives in good yield with 10-20:1 dr. The scope and limitations of these transformations are discussed in detail, as are the effect of substrate sterics and electronics on yield and stereoselectivity. A proposed mechanism of these transformations is presented along with a model that rationalizes the stereochemical outcome of the reactions.

| S-EPMC2700004 | biostudies-literature

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides - scope and limitations.

Project description:The scope of a flexible route to unsymmetrically functionalized bipyridines is described. Starting from 1,3-diketones 1a-e, the corresponding β-ketoenamines 2a-e were converted into different β-ketoenamides 3a-g by N-acylation with 2-pyridinecarboxylic acid derivatives. These β-ketoenamides were treated with a mixture of TMSOTf and Hünig's base to promote the cyclocondensation to 4-hydroxypyridine derivatives. Their immediate O-nonaflation employing nonafluorobutanesulfonyl fluoride provided the expected 4-nonafloxy-substituted bipyridine derivatives 5a-g in moderate to good overall yields. The bipyridyl nonaflates are excellent precursors for palladium-catalyzed reactions as demonstrated by representative Suzuki and Sonogashira couplings. Thus, a library of specifically substituted bipyridine derivatives was generated, showing the versatility of the simple 1,3-diketone-based approach to this important class of ligands.

| S-EPMC4979911 | biostudies-literature

Split Green Fluorescent Proteins: Scope, Limitations, and Outlook.

Project description:Many proteins can be split into fragments that spontaneously reassemble, without covalent linkage, into a functional protein. For split green fluorescent proteins (GFPs), fragment reassembly leads to a fluorescent readout, which has been widely used to investigate protein-protein interactions. We review the scope and limitations of this approach as well as other diverse applications of split GFPs as versatile sensors, molecular glues, optogenetic tools, and platforms for photophysical studies.

| S-EPMC6537611 | biostudies-literature

The Amadori Rearrangement for Carbohydrate Conjugation: Scope and Limitations.

Project description:The Amadori rearrangement was investigated for the synthesis of C-glycosyl-type neoglycoconjugates. Various amines including diamines, amino-functionalized glycosides, lysine derivatives, and peptides were conjugated with two different heptoses to generate non-natural C-glycosyl-type glycoconjugates of the d-gluco and d-manno series. With these studies, the scope and limitations of the Amadori rearrangement as a conjugation method have been exemplified with respect to the carbohydrate substrate, as well as the amino components.

| S-EPMC5094532 | biostudies-literature

Synthesis of diverse indole libraries on polystyrene resin - Scope and limitations of an organometallic reaction on solid supports.

Project description:The synthesis of diverse substituted indole structures on solid supports is described. The immobilization of nitrobenzoic acid onto Merrifield resin and the subsequent treatment with alkenyl Grignard reagents delivered indole carboxylates bound to solid supports. In contrast to results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and limitations are presented.

| S-EPMC3458737 | biostudies-literature

Mechanism of the Aza-Piancatelli Reaction: Scope and Limitations of Furan Substitution in Donor-Acceptor Stenhouse Adduct Synthesis.

Project description:The aza-Piancatelli reaction has been widely used to synthesize donor-acceptor Stenhouse adducts (DASAs), a new class of molecular photoswitches with unique properties. However, the substitution pattern of furan cores has been limited to position 3, as 3,4-disubstituted furans remain unreactive. Herein, we explore the aza-Piancatelli reaction mechanism using density functional theory (DFT) calculations to understand the influence of the different substituents on the reactivity. We found that all the reaction pathways are kinetically accessible, but the driving force of the reaction is lost in disubstituted furans due to the loss of conjugation in the DASA products. Finally, a simple model is proposed to guide the design of synthetic routes using this reaction.

| S-EPMC9261078 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data